ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()
In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data() On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic. Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it: - in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation; - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written. Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00).
CVE-2026-43186
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-43186
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "f4d9d4b8fd839719d564651671e24c62c545c23b",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "fb3c662fafebc5b9d74417ed1de8759f6bb72143",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "632d233cf2e64a46865ae2c064ae3c9df7c8864f",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "0591d6509c2ff13f09ea2998434aba0c0472e978",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "e90346a2f1e8917d5760a44a1f61c44e3b36d96b",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "ea3632aefc04205436868541638e26f4a74d5637",
"versionType": "git"
},
{
"status": "affected",
"version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0",
"lessThan": "6db8b56eed62baacaf37486e83378a72635c04cc",
"versionType": "git"
}
],
"programFiles": [
"include/net/ioam6.h",
"net/ipv6/exthdrs.c",
"net/ipv6/ioam6.c",
"net/ipv6/ioam6_iptunnel.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.202",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.165",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.128",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.75",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.16",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.6",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/ioam6.h",
"net/ipv6/exthdrs.c",
"net/ipv6/ioam6.c",
"net/ipv6/ioam6_iptunnel.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43186
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #40039 · Revision 1
- Added to Heist Feed
- Publisher date